Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 221638
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1238 PM EDT TUE JUL 22 2014

.SYNOPSIS...
A STATIONARY FRONT ALONG THE COAST WILL SLOWLY MOVE INLAND TODAY AND
DISSIPATE TONIGHT. BERMUDA HIGH PRESSURE WILL BUILD INTO THE AREA
WEDNESDAY AND THURSDAY. A COLD FRONT WILL APPROACH FROM THE
NORTHWEST LATE THURSDAY...STALLING NEAR THE COAST FOR THE WEEKEND.
ANOTHER COLD FRONT WILL APPROACH FROM THE NORTHWEST MONDAY OR
TUESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM TUESDAY...CONVECTIVE COVERAGE IS A LITTLE LESS THAN I
HAD ANTICIPATED AT NOON BUT RAINFALL RATES WHERE STORMS ARE
OCCURRING ARE QUITE LARGE. RADAR IS ESTIMATING UP TO 1.75 INCHES PER
HOUR WITH THE ACTIVITY NEAR CASTLE HAYNE IN NORTHERN NEW HANOVER
COUNTY. NO CHANGES ARE PLANNED AT THIS TIME TO THE FLOOD WATCH...
ALTHOUGH THE NEW 12Z NAM AND GFS ARE SUGGESTING LESS CONVECTIVE
COVERAGE MAY OCCUR INLAND...AND THE WATCH COULD BE DROPPED WEST OF
I-95 WITH THE 3 PM UPDATE. PREVIOUS DISCUSSION FROM 1000 AM
FOLLOWS...

THE SYNOPTIC PATTERN FEATURES AN UPPER LOW OVER COASTAL ALABAMA AND
AN UPPER RIDGE OFF THE SOUTHEAST COAST. IN BETWEEN THESE TWO
FEATURES A STREAM OF DEEP TROPICAL MOISTURE BEING LIFTED FROM THE
CARIBBEAN ACROSS FLORIDA AND OVER THE CAROLINAS. AT THE SURFACE AN
OLD STATIONARY FRONT STILL LIES FROM NEAR CAPE FEAR TO EAST OF
GEORGETOWN SC.

WIDESPREAD LOW STRATUS AND FOG LAST NIGHT IS TAKING ITS TIME BURNING
OFF INLAND. THE STATIONARY FRONT OFFSHORE WILL PROBABLY REDEVELOP IN
THE NEXT 1-2 HOURS ALONG THE EASTERN EDGE OF THE LOW CLOUDS...WITH
THIS BOUNDARY BECOMING THE PREFERENTIAL DEVELOPMENT REGION FOR NEW
SHOWERS AND THUNDERSTORMS. PRECIPITABLE WATER VALUES ARE
EXCEPTIONAL: 2.1 TO 2.3 INCHES ON MODEL SOUNDINGS. THIS COUPLED
WITH SLOW STORM MOVEMENT SHOULD LEAD TO MORE HEAVY RAINFALL AND
FLOODING THIS AFTERNOON. A FLOOD WATCH WAS ISSUED EARLIER TODAY AND
STILL APPEARS WARRANTED...ESPECIALLY FOR REGIONS EAST OF INTERSTATE
95.

FLASH FLOOD GUIDANCE VALUES FROM THE NWS SOUTHEAST RIVER FORECAST
CENTER ARE 1.5 TO 2.5 INCHES IN 1 HOUR...AND 2.2 TO 3.2 INCHES IN 3
HOURS. THESE VALUES WILL NOT BE HARD TO REACH GIVEN THE ANTICIPATED
SETUP THIS AFTERNOON. FREEZING LEVELS HAVE RISEN FROM YESTERDAY AND
WILL APPROACH 16000 FEET THIS EVENING. THIS WILL CREATE A VERY DEEP
REGION FOR EFFICIENT WARM-CLOUD COALESCENCE RAINFALL PROCESSES.
RAINFALL AMOUNT FORECASTS ON THE BROAD SCALE ARE 0.5 TO 1.0 INCH
EAST OF INTERSTATE 95 WITH ISOLATED AREAS PROBABLY PICKING UP
ANOTHER 4-5 INCHES. WEST OF I-95 STORM COVERAGE MAY BE A LITTLE MORE
SPARSE WITH RAINFALL RATES WILL BE JUST AS HEAVY.

HIGHS TODAY SHOULD RANGE FROM 83 ON THE BEACHES TO THE MID 80S
INLAND. SOME UPPER 80S MAY STILL OCCUR ACROSS THE PEE DEE REGION
ASSUMING LOW STRATUS BURNS OFF ON SCHEDULE.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 330 AM TUESDAY...SHOULD SEE A LULL IN WIDESPREAD
CONVECTION WED AS UPPER RIDGE BUILDS IN BRIEFLY AND A DEEP SW FLOW
WILL VEER BECOMING MORE WESTERLY ALLOWING FOR SOME MID LEVEL
DRYING. THE DEEPEST MOISTURE WILL REMAIN TO OUR EAST OVER THE
WATERS WHERE PCP WATER VALUES WILL BE MAXED OUT AROUND 2.3 INCHES
WED AFTN. EXPECT MORE LOCALIZED CONVECTION ON WED ESPECIALLY ALONG
THE SEA BREEZE IN THE AFTN AND THE WESTERLY COMPONENT TO THE WINDS
SHOULD HELP TO KEEP SEA BREEZE PINNED CLOSER TO THE COAST AND HELP
STORMS MOVE OFF TO THE EAST OVER THE WATERS.

BY THURS FLOW WILL INCREASE OUT OF THE SOUTHWEST AS GRADIENT
TIGHTENS AS COLD FRONT MOVES IN FROM THE NORTHWEST. MODELS LOOK
FASTER WITH THE DIGGING MID TO UPPER TROUGH PUSHING THE COLD
FRONT INTO THE COASTAL CAROLINAS BY THURS NIGHT. THE DAY SHOULD
START OUT DRIER WITH PCP WATER VALUES DOWN CLOSER TO 1.5 INCHES.
NAM AND ECMWF ARE A LITTLE MORE AGGRESSIVE WITH SOUTHWARD
PROGRESSION OF FRONT SHIFTING IT SOUTH OF AREA BY FRI MORNING
WHILE THE GFS HANGS IT UP RIGHT ALONG THE COAST AS THE H5 TROUGH
LIFTS NORTH. EITHER WAY...SHOULD SEE STRONGER AND MORE NUMEROUS
SHWRS/TSTMS ON THURS AHEAD OF FRONT INLAND INITIALLY AND THEN
SHIFTING CLOSER TO THE COAST. WILL NEED TO KEEP A CLOSE EYE ON HOW
FAST THIS SYSTEM MOVES.

TEMPS WILL RISE THROUGH THE PERIOD REACHING NORMAL OR SLIGHTLY
ABOVE NORMAL AS HEIGHTS RISE THROUGH MID WEEK AS RIDGE BUILDS IN
ON WED. TEMPS MAY LOWER THURS AS TROUGH DIGS DOWN LOWERING H5
HEIGHTS AND PRODUCING MORE IN THE WAY OF CLOUDS AND PCP AHEAD OF
COLD FRONT. OVERNIGHT LOWS SHOULD REMAIN ABOVE NORMAL...IN THE MID
70S...IN A CLOUDIER AND MORE HUMID AIR MASS.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 330 AM TUESDAY...COLD FRONT MAY BE HUNG UP RIGHT ALONG THE
COAST FRI MORNING BUT NAM WANTS TO PUSH IT SOUTH AND EAST OF AREA
LEAVING HIGH PRESSURE IN CONTROL. NOT CONFIDENT THAT THE BOUNDARY
WILL GET TOO FAR SOUTH AS H5 TROUGH LIFTS NORTH LEAVING A VERY
BROAD MID TO UPPER TROUGH ANCHORED OVER THE GREAT LAKES
MAINTAINING MORE OF A SW FLOW ALOFT AND NOT GIVING MUCH OF PUSH TO
THE COLD FRONT. THEREFORE WILL KEEP FRONT JUST TO OUR NORTHWEST
ON FRI. DEEP SW FLOW WILL KEEP A WARMER AND MORE HUMID AIR MASS
OVER THE AREA LEAVING POTENTIAL FOR LOCALIZED CONVECTION THROUGH
THE WEEKEND.

MID TO UPPER TROUGH WILL DIG DOWN FROM THE GREAT LAKES COME MONDAY
PUSHING ANOTHER COLD FRONT INTO THE CAROLINAS. THIS WILL PRODUCE
MORE WIDESPREAD CONVECTION IN INCREASED UPPER LEVEL SUPPORT LATER
ON MONDAY. ONCE AGAIN UPPER LEVEL TROUGH WILL REMAIN TO OUR WEST
LEAVING A FLOW RUNNING MORE PARALLEL TO FRONT AND NOT GIVING IT
TOO STRONG OF A PUSH THROUGH THE AREA. THEREFORE MAY NOT SEE TOO
MUCH OF AN AIR MASS CHANGE BEHIND FRONT.

OVERALL EXPECT GREATEST POTENTIAL FOR MORE WIDESPREAD CONVECTION
EARLY FRI AND AGAIN MON AFTN INTO EARLY TUES...BUT EXPECT MORE
TYPICAL DIURNAL TYPE SHWR ACTIVITY MOST DAYS. SOME DRIER AIR SHOULD
MAKE IT INTO INLAND AREAS ON FRI AND ON TUES BEHIND FRONTS...BUT
WILL MOST LIKELY REMAIN JUST TO THE WEST OF FORECAST AREA. TEMPS WILL
BASICALLY BE ABOVE CLIMO WITH OVERNIGHT LOWS IN THE 70S AND DAY
TIME HIGHS INTO THE 90S MOST DAYS WITH LOWER TEMPS EXPECTED. AS
TROUGH DIGS DOWN THURS INTO FRI AND AGAIN MON INTO TUES MAY SEE
BELOW NORMAL TEMPS IN LOWERED H5 HEIGHTS.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AS OF 18Z...WIDESPREAD MVFR/IFR IS EXPECTED THROUGH TONIGHT AS
SHRA/TSRA COVERAGE INCREASES OVER THE NEXT SEVERAL HOURS. SHRA/TSRA
WILL TAPER OFF...BUT DO EXPECT MVFR/IFR/LIFR THROUGH THE OVERNIGHT
HOURS DUE TO LOW CIGS AND AREAS OF REDUCED VISIBILITIES.

LATEST RADAR IMAGERY DEPICTS SHRA/TSRA CONTINUING TO BECOME MORE
WIDESPREAD ACROSS THE AREA...PRODUCING HEAVY DOWNPOURS AT
TIMES...AREAS OF FOG AND LOW CIGS. AS A RESULT...EXPECT MVFR/IFR TO
PERSIST THROUGH TONIGHT...THOUGH CANNOT RULE OUT BRIEF IMPROVEMENTS
TO VFR AT TIMES AS VARYING CIG HEIGHTS ARE MOVING ACROSS THE AREA.
EAST-SOUTHEASTERLY WINDS ARE EXPECTED THROUGH THE DAY AOB 10 KTS.
SHRA/TSRA WILL TAPER OFF THIS EVENING...BUT WILL STILL SEE
WIDESPREAD MVFR/IFR/POSSIBLE LIFR DUE TO LOW CIGS AND AREAS OF
FOG...ESPECIALLY INLAND. INTO WEDNESDAY MORNING...EXPECT LIGHT WINDS
WITH PERSISTENT LOW CLOUDS AND POSSIBLE VCSH/VCTS THROUGH THE END OF
THE PERIOD.

EXTENDED OUTLOOK...CHANCE OF SHOWERS/TSTMS WILL PERSIST THROUGH THE
EXTENDED PERIOD. EXPECT PREDOMINANTLY VFR CONDITIONS WITH TEMPO
PERIODS OF MVFR/IFR CIGS/VSBYS IN STORMS.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 AM TUESDAY...WINDS ARE VEERING SOUTHEASTERLY ACROSS THE
NC WATERS AS THE OLD FRONT BEGINS TO SHIFT INLAND. WE ARE STILL
HOLDING ONTO A NORTH-NORTHEAST WIND OVER COASTAL SOUTH CAROLINA...
BUT EVEN HERE WINDS SHOULD BECOME SOUTHERLY BY LATE IN THE DAY.
SHOWERS AND THUNDERSTORMS ARE DEVELOPING ON A LINE FROM WILMINGTON
TO OAK ISLAND WITH RATHER CHAOTIC MOVEMENT NOTED SO FAR. MARINERS
ARE NOT IN THE CLEAR AS THIS ACTIVITY MAY DEVELOP OR SPREAD OFFSHORE
THIS AFTERNOON. PREVIOUS DISCUSSION FROM 1000 AM FOLLOWS...

THE OLD STATIONARY FRONT IS STILL HERE..AND AT 10 AM EXTENDS ROUGHLY
FROM CAPE FEAR SOUTHWESTWARD ACROSS THE COASTAL WATERS EAST OF
GEORGETOWN. THE OVERALL WEATHER PATTERN IS RETROGRADING
TODAY...MEANING IT IS SHIFTING WESTWARD RATHER THAN THE TYPICAL
EASTWARD PROGRESSION WE SEE. THE FRONT SHOULD SHIFT INLAND BY MID TO
LATE AFTERNOON...WITH WINDS VEERING FROM THE NORTHEAST AROUND TO THE
SOUTH BY LATE IN THE DAY. SPEEDS WILL ALSO INCREASE WITH THE TIGHTER
PRESSURE GRADIENT ON THE EAST SIDE OF THE FRONT BETWEEN IT AND
BERMUDA HIGH PRESSURE WELL OFFSHORE. THIS WILL INCREASE WIND SPEEDS
TO NEAR 15 KNOTS BY EVENING...WITH GUSTS EXCEEDING 20 KNOTS AT TIMES
LATE THIS EVENING.

WIDESPREAD THUNDERSTORM ACTIVITY OFFSHORE THIS MORNING WILL SHIFT
LARGELY ONSHORE BY THIS AFTERNOON. WHILE THIS WILL DECREASE THE
NUMBER OF STORMS OCCURRING OVER THE COASTAL WATERS THERE SHOULD
STILL BE A FEW STORMS OFFSHORE EVEN THIS AFTERNOON. COVERAGE OF
STORMS MAY ACTUALLY INCREASE OVERNIGHT.

SEAS CURRENTLY AROUND 3 FEET WILL BUILD TOWARD 4 FEET AWAY FROM
SHORE TONIGHT IN RESPONSE TO THE INCREASING SOUTH WINDS. WAVE
SPECTRA WILL BE EVENLY SPLIT BETWEEN 7 SECOND SOUTHEAST SWELL AND
SHORTER PERIOD WIND WAVES.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 330 AM TUESDAY...ATLANTIC HIGH PRESSURE WILL BUILD WESTWARD
THROUGH MID WEEK WITH A S-SW RETURN FLOW UP TO 15 KTS. A COLD
FRONT WILL APPROACH FROM THE NORTHWEST LATE THURS WITH WINDS
POSSIBLY MAKING IT UP TO 20 KTS IN TIGHTENED GRADIENT FLOW. SEAS
2 TO 4 FT ON WED INTO THURS WILL INCREASE UP TO 3 TO 5 FT BY LATE
THURS AHEAD OF COLD FRONT BUT WNA MODEL REMAINS CONSISTENT KEEPING
SEAS BELOW SCA THRESHOLDS...ALTHOUGH A PRECAUTIONARY STATEMENT MAY
BE NEEDED.

LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 330 AM TUESDAY...COLD FRONT REACHES INTO THE CAROLINAS EARLY
FRI BUT WILL MOST LIKELY STALL AND DISSIPATE OVER INLAND CAROLINAS
OVER THE WEEKEND. EXPECT TO MAINTAIN A SW FLOW AROUND BERMUDA HIGH
WEAKENING AS GRADIENT RELAXES THROUGH FRIDAY INTO SATURDAY AS
FRONT DISSIPATES OVER THE CAROLINAS. SEAS UP TO 3 TO 5 FT EARLY
FRI WILL FALL BACK DOWN TO 2 TO 4 FT THROUGH LATE FRI INTO
SATURDAY.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...FLOOD WATCH UNTIL 6 PM EDT THIS EVENING FOR SCZ017-023-024-032-
     033-039-053>056.

NC...FLOOD WATCH UNTIL 6 PM EDT THIS EVENING FOR NCZ087-096-099-
     105>110.

MARINE...NONE.

&&

$$

NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...SGL





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